A pressure relief valve (RV) is a type of valve used to control or limit the pressure in a system or vessel which can build up by a process upset, instrument or equipment failure, heat, etc. The pressure is relieved by allowing the pressurized fluid to flow from an auxiliary passage out of the system. The relief valve is designed or set to open at a predetermined set pressure to protect pressure vessels and other equipment from being subjected to pressures that exceed their design limits. When the set pressure is exceeded, the relief valve becomes the “path of least resistance” as the valve is forced open and a portion of the fluid is diverted through the auxiliary route. As the fluid is diverted, the pressure inside the vessel will drop.
For example, in a chlorination system (or other water treatment systems), a pressure relief valve may be utilized to prevent the chlorinator from becoming over pressurized. Water may be pumped into the chlorinator by a pump. The pump may be capable of generating water pressure of, for example, between 10 to 60 psig. However, the chlorinator may be designed to operate at pressures up to 50 psig. Thus, there is clearly a need for a pressure relief valve associated with a chlorination system.
One problem with known pressure relief valves is that the pressure relief valve has corrosive parts that are exposed to the fluid. As should be understood, this is especially problematic for chlorination systems, or other water treatment systems.
Another problem with known pressure relief valves is that when sprung, the pressure drops in the system, but does not drop all the way to zero pressure. Some systems, like chlorination systems or water treatment systems, may desire the system to be completely purged of the fluid when the pressure relief valve is opened. This requires a “full flow” pressure relief valve, i.e., one that drops the pressure in the system all the way to zero.
The instant invention is designed to address the above mentioned problems.